[tree-ssa] Garbage collector x bb annotations

[Daniel Berlin]

On Tue, 7 Oct 2003, Zdenek Dvorak wrote:

> Hello,
>
> I have just run into the following problem: dom_children get released by
> ggc_collect call in tree-ssa-pre.

This can only occur if they aren't marked, but are ggc allocated. They
shouldn't be, if they are.

>Allocating them by ggc seems wrong to
> me, since basic block annotations are allocated from obstack and
> invisible to garbage collector.

It is wrong.
They will *always* be collected if this is the case.

It must not show up because we push context before starting our
PRE'ing of expressions, so unless we redo dom children, we'd not collect
them.
>
> Zdenek
>